Gas compressor



April 14 1931 r. E ROBBENNQLT GAS COMPRESSOR Filed p e, 1929 Housing INVENTOR JZOg/dEJBObbemZOZ/t ATTQRN Y Patented Apr. 14, 193i PATENT OFFICE FLOYD E. ROBBENNOLT, F SAGINAW, MICHIGAN 1 I 3 GAS COMPRESSOR Application filed September 6, 1929. Serial No. 390,700.

This invention relatesto vertical enclosed ammonia gas compressors that comprise a belt-driven crank shaft, a vertically reciprocating trunk piston operating in an upright 5 cylinder and valve mechanisms whereby the piston draws in ammonia gas on the down stroke and compresses anddischargesit on the up stroke. Compressor to which my invention is applicable have an enclosed crank I 1 case partly filled with oil for splash lubrication of the crank shaft bearings and cylinder walls. The crank case also has at one side a closed housing for an end of the crank shaft and at the other side a packed gland in which 1 the crank shaft is rotated by a belt pulley.

It may be noted that in the ordinary oper ation of a compressor of this type there unavoidably comes to the compressor, along with the ammonia gas to be compressed, more 29 or less liquid ammonia which enters the suction inlet. During the upward stroke of the trunk piston some of the liquid finds its way down past the piston and into the crank case where it causes excessive foaming as soon as the compressor warms up, because the liquid ammonia evaporates and the resulting ammonia gas and oil mix with avidity and the whipping action of the rapidly rotating crank and connecting rod produce foam con- 30 sisting of oil particles and gas whose pressure tends constantly to increase.

Two disadvantages, namely, excessive wear of the gland packing and oil priming, are inherent in such compressors. Both result from this building up'of ammonia gas pressure Within the crank case during the normal operation of the compressor.

Harmful wear of the gland packing is caused by a persistent endwise thrust of the crank shaft rubbing the crank slab against the end of the gland bearing, thereby heating it and injuring the packing. Such endwise thrust of the shaft is brought about by pressure of ammonia gas accumulating within the crank case and finding its way along the shaft bearing and into the housing that encloses the end of the crank shaft and there exerting pneumatic pressure against the end area of the shaft.

Oil priming occurs when the built up gas pressure in the crank case forces lubricating oil from the crank case upward between the cylinder wall and the rings of the trunk piston and thence into any charge of gas which is in the act of being compressed by the piston. The gas goes thence into the refrigerating pipe system Where it reduces the rate of heat transfer and causes other serious and well-known disadvantages in the operation of the refrigerating system.

The seriousness of oil priming trouble can be made apparent by reference to a typical instance of a compressor equipped with ten and a half inch diameter piston. This compressor was found to be pumping into the refrigerating system thirty to seventy-five gallons of lubricating oil per day. In this instance the bottom part of the trunk piston skirt was worn two hundredths inch after only four or five weeks of operation.

After prolonged study and experimenting I have discovered a simple and inexpensive means for preventing the unavoidable building up of ammonia gas pressure within the crank case, thereby curing both of the stated difiiculties, gland packing wear and oil priming. I accomplish both of these objects by a device that is useful and novel, although simple.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a vertical sectional view of a compressor with my improvement applied thereto.

Fig. 2 is a diagrammatic view of the lower part of a compressor, partly broken away, to show' the preferred arrangement of the device in relation to the cranks of a compressor. i

As is clearly shown in the drawings the device comprises a vent pipe or conduit 1, an end 1a connected to the gas intake 2 of the compressor, the other end 1?) communicating with the interior of the crank case 3 below the piston 4.

I preferably provide the end 10 of the vent pipe with an oil deflecting and separating element, preferably an outwardly flared mouth piece 161, so all the particles of foam projected by the cranks 5, along the end 1c of the pipe are deflected outwardly by the r mouth piece; '(jonsequently they fly away from the orificeof intake 1d and there is presented at that place a zone which is comparatively free from oil particles; Through this zone the gas, freedfrom'oil spray, passes relatively slowly into the vent conduitl.

I have discovered that va certain co-opera tive relationship must exist betwee'n the ro- V tating cranks'andthe' flared suction end 1d of the relief pipe in order to most effectively: sep arate: the gas from the particles of oil. To attain that relationship the orifice ofthe flared end 145 of the conduit must be located with respect to thecircle of crank travel so.

that thestorm of spray particles, driven at high speed by the rapidly rotating cranlnis constrained to shoot along the .conduitand nozzle'andthence outwardly away from the e nozzleorificefin a direction substantiallyop:

, gas which is being drawn into the orifice. {Such separator action is most effective when posite'tothe clirectionof flowof the ammonia fthe nozzletopening is located closeto the circle ofrrevolution of some part of crank5 and practically tangent thereto, althoughit may conceivably be located in; any ,place where the spray particles hav'e suificientveflocity andsuitable direction to accomplish the stated. object. a

' duced-byaenozzle lthe area of whoseintake orifice is abouttwenty-five times the ar fi 0f- :the small end; for example aIconduit 1, one

f. conduit as equipped with an outwardly.Jtlarf '1 1 y io rthpinchi'd meter; ay" mp ye having an opening one and one-fourth inches diameter; 1 This H proportion prevents any such intensity of gas flow into the bell mouth as might cause oil sprayto'be carried intoit. To adjust this area-ratio a suitable rega lating valve, fiispreferably provided in the conduit.

;Whi1e Ii-haive shown described the a ed m rimay semei s n e dis- 'fpensed with without departing from their;-

gdiliectien offrotation or thecrank to a; po t tionrsubsta ntially tangential toits circle of. I

rotati=on and terminating .anlorificeposif,

tioned substantially-"at theltop of -saidlcircle A an m an nt ol n -th rat of as flew I find that satisfactory resultsare pro.

ing nozzle or mouth piece 101, this beinga .preferred embodiment of my invention, the e r or a through said'conduit, for the purposes set forth. V

2. In a vertical enclosed type ammonia gas compressor having a .closedcrank case,

a cylinder, a piston, a connecting rod and a crank, means for preventing building up of ammonia'gas pressurevin the crankcase comprlsmg a gas conduit communicatingat one end with the gas intake tofthe compressor,

its other end formed to provide an outwardly'flaring mouth piece, said mouth piece projecting into the crankcase in the direction of rotation ofthe crank with its large end locatedgin -the p'athj of spray jets caused thereby, the location of said enlarged end with respect to the jetsbeing suchthat oil thrownbylthe cranks is deflected away from the open end of themonth' piece, while gas content of V the spray is being draw there? into, "for the purposes set forth; H I

3.7111 combination a,gas'}compressor in;

cludin ga cylinder having an intake for gas to be compressed, a rebiprocatngipiston, a closedicrank case, a? crank andlconnecting rod andaiconduit communicatmg with lthe said gas intake'andwith the" crank case, an end of said conduit arranged to extend into the interior of the crank caseinthe direction of rotation of the crank and terminating "in an open mouth positioned substantially v tagential to the upper part of the, circle of rotation of the-crank, and a valvefin said lco'nduit forf controlling the operation.

' LQA structure asset forthQinfclaimQ wherein the lcross sectional area "of the conduit is equal fto approximately :one twenty fifthof thelarea of its intake end; V r 7 A In, testimony whereof, Iaflix my signature. I FLOYD 0LT; 

